Post-stroke individuals have significant balance control deficits compared to healthy older adults, which often lead to musculoskeletal injuries and long-term disability. Previous research has shown that current stroke rehabilitation strategies do not effectively improve balance control. We believe that the lack of rehabilitation effectiveness is in part due to a limited understanding of the compensatory mechanisms used by post-stroke individuals. The overall goal of this project is to better understand how mediolateral balance control mechanisms are impaired and compensated for post-stroke to motivate more targeted interventions that improve balance control. Specifically, we will apply an external lateral stabilizing force to the pelvis during treadmill walking that will reduce the actie balance control requirements and thereby reveal the compensatory mechanisms used to control mediolateral balance. We will focus on mediolateral balance, which requires more active control than sagittal plane balance in healthy subjects. Further, we will seek to investigate whether lateral stabilization improves overall walking performance, which will provide motivation for future testing of its use as a novel gait retraining intervention. We will also investigate immediae carry-over effects of the lateral stabilization to overground walking in order to inform future testing of lateral stabilization as a gait intervention, and determine whether it is an effective assessment tool to distinguish those that can adapt their gait pattern (responders) from those that cannot (non-responders). This project will use an experimental approach that is novel in the post-stroke population, but has been shown effective in healthy adults. The advantage of this approach is that it will reduce the active balance control requirements and thereby isolate the compensatory mechanisms used to control mediolateral balance. This project is therefore likely to have an extremely high clinical impact. If lateral stabilization proves to be beneficial and results in a more natural gait pattern, it may have potential as an effective intervention for improving dynamic balance. Further, lateral stabilization is easily implemented in a clinical setting and may prove to be an effective assessment tool to distinguish those who can adapt their gait from those who cannot.